This invention relates to a central closure for shoes with a rotatably mounted sheave for at least one rope-like tightening element for closing the shoe, in which the sheave is coupled to a gear by an actuating element and can be driven via the latter and the number of revolutions of the sheave can be limited by a stop.
Such a central closure, designed as a rotating closure, is known from EP-0 393 380 B1. The fact that the number of revolutions of the sheave is limited to somewhat less than two full revolutions is necessitated there by application of the pulley principle. In this case, one pulley is formed by the sheave. This has a carrier, which can stop after about one rotation on a rotatable arm, whereby said arm represents the towed sleeve target and can strike with a stop block against a housing edge. In this case, small structural dimensions are sought, even though a longer pull path to close the shoe is necessary.
In this known device, the diameter of the sheave must be selected in accordance with the rope path and the not quite two complete revolutions of the sheave that are possible there. In the case of long pull paths, therefore, the diameter of the sheave is also to be selected suitably large. In the case of this known device, therefore, freedom in the selection of the sizing of the dimensions of this device is greatly restricted.
On the other hand, the number of revolutions of the sheave could be increased by using additional pulleys, so that a longer pull path could be handled by increasing the number of turns on the sheave. This would, however, require a larger structural volume corresponding to the thickness of the additional pulleys.